I have not seen a Death Cert for 1887 let alone for the 1880's. You can contact the Buffalo Department of Health and start there for his Death Cert. It also may be with the Buffalo coroner's office....Do you know what Cemetery he's in ? Those records would tell you who buried him, and what relatives were present at time of burial.
Also, just because his death notice was in the Buffalo New doesn't mean he lived in city. He could have lived on the out skirts of town many fames during that period of time, and many migrate workers too.